Systems and methods for processing audio data are known in the art. Most of these systems and methods are used to process audio data for a known audio environment, such as a two-channel stereo environment, a four-channel quadraphonic environment, a five channel surround sound environment (also known as a 5.1 channel environment), or other suitable formats or environments.
One problem posed by the increasing number of formats or environments is that audio data that is processed for optimal audio quality in a first environment is often not able to be readily used in a different audio environment. One example of this problem is the conversion of stereo sound data to surround sound data. A listener can perceive a noticeable change in sound quality when programming changes from a stereo format to a surround sound format. For example, as the additional channels of audio data for a 5.1 channel surround sound format are not present in a stereo two-channel format, existing surround systems rely on sub-optimal up-mix methods that commonly produce unsatisfactory results. Traditional up-mix methods steer a small number of dominant broadband signal elements around a fixed-channel sound field based on time domain energy measurements. The resulting surround sound experience is commonly unstable and spatially indistinct.